Future of water on public display at San Diego’s Water Purification Demonstration Project

The City of San Diego opens the doors this summer to a facility that is testing whether it
could provide a new local source of water for San Diego. Located in northern San Diego, the
Advanced Water Purification Facility is a small-scale, state-of-the-art water purification facility
that purifies one million gallons of recycled water every day to a level similar to distilled water
quality.
The facility is one component of the City’s Water Purification Demonstration Project that is
examining the safety and cost of purifying recycled water. If this project is approved to go full-
scale, the purified water would blend with the City’s imported supplies at San Vicente Reservoir
and would become part of the City’s drinking water supply. As another component of the
Demonstration Project, the City is studying San Vicente Reservoir and the potential effects of
adding purified water to it. During the year-long test phase, purified water will not be sent to
San Vicente Reservoir or the City’s drinking water system; instead, the purified water will be
added to the City’s recycled water system.
San Diego is testing water purification as a means to develop a locally controlled, supplemental
water supply. San Diego’s semi-arid region is at the end of pipelines that import water from
hundreds of miles away. The City needs to develop local, reliable water sources to lessen its
dependence on expensive and limited imported water supplies.
“Our City has been both creative and aggressive in trying to diversify our water supply. The
less we rely on importing water from outside San Diego County, the more we control our own
destiny,” San Diego Mayor Jerry Sanders said. “A locally produced supply of water could be an
important option for us.”
All wastewater in San Diego undergoes treatment to remove harmful contaminants, making
it safe enough to be discharged into the ocean. Some wastewater is diverted to the City’s
recycled water facilities, where it is further treated and then used for irrigation and industrial
purposes. A portion of the recycled water produced at the North City Water Reclamation Plant
will be sent to the Advanced Water Purification Facility.
At the facility, the recycled water undergoes the multi-barrier purification process, which
includes membrane filtration, reverse osmosis, and advanced oxidation with ultraviolet
disinfection and high-strength hydrogen peroxide. The multi-barrier approach of consecutive
treatment steps work together to remove or destroy all unwanted materials in the water and
produces one of the most pristine supplies of water available anywhere. Each step in the
process also includes continuous water quality monitoring. The City thoroughly examines the
safety of the water through laboratory tests and computer analysis to ensure that it meets
public health standards.
The data from the Demonstration Project will be thoroughly examined, and the results will
determine the safety and cost of a full-scale water purification and reservoir augmentation
project. After the test phase is complete, the City Council and Mayor will decide whether to
implement a full-scale project.
“This Demonstration Project will provide the answers San Diego needs before taking the next
step with purified water,” said Mayor Sanders. ”We owe it to our citizens to see if we can come
up with an alternative source of local, safe and relatively inexpensive drinking water.”
The same water purification process is already used around the world. Just north of San Diego,
Orange County operates the world’s largest water purification plant. The Orange County
Groundwater Replenishment System produces up to 70 million gallons a day of ultra clean
water to provide safe and reliable drinking water for nearly 600,000 residents. The purified
water is produced from secondary-treated wastewater and injected into the county’s drinking
water aquifer.
Visitors are welcome and encouraged to tour the Advanced Water Purification Facility through
summer 2012. Guests who participate in the AWP Facility tour will gain a better understanding
of the Demonstration Project and what role the facility plays in this testing phase. Following an
introductory presentation, tour participants will take a walking tour through the facility to view
the water purification technology equipment up close. At the end of the tour, guests will view
the purified water produced at the facility. To register for a tour, visit www.purewatersd.org/
tours.shtml. For more information about the City of San Diego’s Water Purification
Demonstration Project, visit www.purewatersd.org, email purewatersd@sandiego.gov, or call
(619)533-7572.

by Marsi A. Steirer, Water Purification Demonstration Project Director,
City of San Diego, Public Utilities Department